76 MODEL AVIATION
IN RECENT COLUMNS I discussed the unusual valveless
four-stroke model engines made by the British RCV company
(www.rcvengines.com). The results of my tests on its RCV58-CD
(“CD” means Crankshaft Drive) impressed me so greatly that I
soon acquired one of the “in-line” engines: the RCV60-SP.
(These in-line power plants are also available in 90 and 120 cu.
in. displacements.)
This extraordinary design differs in almost every way from
any model engine I’ve ever run. Besides providing the rotary
intake and exhaust valve functions for the 60-SP’s four-stroke
operation, its 2:1 gear-driven rotating cylinder sleeve also drives
the propeller. That makes the propeller rpm exactly half that of
the engine’s crankshaft.
This gearing-down feature allows the 60-SP to turn largediameter,
high-pitch propellers. From that it gains the same
efficiency improvement that so many of today’s electric-powered
RC models get from their reduction gears.
RCV recommends the APC 16 x 12 propeller for the 60-SP.
I’ve tried that, a Master Airscrew Classic 18 x 8, and two 16 x 8s
with wider blades than APC uses. All ran well on the 60-SP at
full-throttle propeller rpm between 4,400 (with the 18 x 8) and
5,300 (using either 16 x 8). (RCV advises a maximum propeller
speed of roughly 5,500 rpm, to avoid any possibility of damage
from over-revving.)
RCV engines (both types) use the lowest-height pistons I’ve
ever seen in model engines. The side height of the 60’s piston is
just half its diameter.
(For 70 years the usual practice for model-engine pistons has
been to make them at least as tall as their diameters. The idea
was to resist “piston cocking”—a tendency to tilt from the side
force exerted on the piston by its connecting rod whenever the
rod is in any position during its travel other than straight along
the cylinder centerline.)
After breaking in my 60-SP, I took it apart—to check for
Joe Wagner
T h e E n g i n e S h o p
212 S. Pine Ave., Ozark AL 36360
The British-made RCV60-SP comes with all necessary mounting
hardware. No separate engine mount is needed.
The optional accessory starting adapter fits into hex socket
screw at engine’s rear. It makes starting positive and safe.
Starting the 60-SP is quick and easy. (The test stand shown has
provisions for running several engines at once.)
The in-line configuration makes neatly cowled-in installations
easy. The small muffler does a fine job of sound reduction.
09sig3QXD 6/24/04 8:37 am Page 76
signs of wear and reposition its ports.
(More about that later in this column.) I
found no visible wear to anything! The
RCV’s steel piston (equipped with a
single thin ring) showed no trace of side
scuffing, despite its shortness. One reason
for that is the RCV’s hardened-steel
cylinder sleeve has a smooth, continuous
bore. It needs no port cutouts. That lets
the piston move with uniform,
uninterrupted side support from one end
of its stroke to the other.
I also closely examined the gear teeth.
Previous in-line model-engine designs
using bevel gear drives (e.g., the twostroke
glow .29s my old friend Clarence
Lee made 50 years ago) suffered geartooth
breakage. That was from fatigue
failure caused by the fact that the same
tooth on the “driving” gear had to absorb
the impact from each firing impulse from
the piston over and over and over—200
times every second the engine ran.
This isn’t a problem in the RCV
designs! They use hardened-steel helicaltype
bevel gears which distribute the peak
driving impulses over two meshing teeth
in each gear rather than just one.
Looking into the 60-SP’s operating
principle in detail, it has a conventional
piston, a connecting rod, and a crankshaft
assembly. The crankshaft spins in dual
ball bearings and includes a bevel gear.
That drives a mating 2:1 gear on the
cylinder sleeve’s base. At the front end of
the rotating cylinder (which also runs in
dual ball bearings) is the combustionchamber
section; ahead of that is the
propeller drive shaft.
The RCV’s combustion chamber—with
an inside diameter of approximately half
the cylinder bore—has a single radial port
September 2004 77
Partial disassembly shows RCV’s construction. Crankcase and
shaft are at left; gear-driven rotary sleeve drive is at right.
Rossi’s amazingly wide range of glow plugs provides maximum
power options for any size and type of glow engine.
Since 1948 Fox Manufacturing
Company has been producing
high quality model airplane
engines, glow plugs and other
accessories. Fox has become a
name modelers can trust when
it comes to durability, power,
and performance at an
affordable price. (479) 646-1656
Fax (479) 646-1757
5305 Towson Avenue
Fort Smith, AR 72901
www.foxmanufacturing.com
email: [email protected]
09sig3QXD 6/24/04 8:37 am Page 77
September 2004 79
on its side. As the sleeve spins, this port
lines up first with the intake (carburetor)
opening to admit a fresh fuel/air charge,
then with the glow plug for the firing
stroke, and then with the exhaust. This
cycle repeats for each revolution of the
propeller.
As with conventional-design fourstroke
model engines, the RCV’s
incoming fuel/air mixture doesn’t pass
through the crankcase. Yet the moving
parts there—plus all four ball
bearings—receive more than adequate
lubrication. That comes from oil the
combustion pressure forces through the
minute clearance gaps between the
rotating sleeve and its outer housing.
My RCV60-SP runs quite cleanly, yet
the utter lack of moving-parts wear—
including the gear teeth—after more
than two hours of test running shows
that they’re well lubricated indeed.
The SP-series RCV engines require
“radial mounting” to a solid-plywood
firewall. To ensure firm attachment,
they come with a metal backplate (for
the rear side of the firewall) and a set of
socket-head metric capscrews and
washers. I found mounting the RCV a
bit tedious because the capscrews are
located close to the engine case. A onequarter
turn at a time with a standard
Allen wrench was all I could manage.
Starting an RCV SP engine is also
different! The external end of its
crankshaft contains a socket-head screw
used as a driver key, and a separately
available adapter fitted onto the shaft of
a standard electric starter provides the
starting action. (I tried several times to
start my 60-SP by hand-flipping the
propeller. It didn’t work.)
RCV engines start best when rather
“wet.” I finger-choke the carburetor
inlet while hand-flipping the propeller
until I can feel fuel against my fingertip.
Then I connect the glow plug and apply
the starter with the throttle set slightly
less than half open. The RCV fires right
up!
I use Omega 10%-nitromethane fourstroke
fuel. It meets RCV’s
recommendations for nitromethane
content and oil percentage exactly and
provides plenty of power. In fact, I had
to attach an “anchor cable” to my
portable engine test stand to prevent
full-throttle thrust from the 18-inch
propeller from pulling that 40+-pound
rig around on my workshop’s deck.
Complete with its mounting plate,
screws, and muffler, the 60-SP weighs
23 ounces. (For comparison, the new
Rossi two-stroke .60 weighs 28 ounces
with its muffler but without a mount.)
However, the 60-SP is somewhat bulky;
it’s noticeably bigger than an O.S. FS-
70 II Surpass.
While test-running my 60-SP, I
noticed its distinctly different “feel.”
Because its piston runs fore and aft
instead of up and down, the main
Mr. NiCd’s BATTERIES AMERICA
www.batteriesamerica.com
Summer 2004 Specials (Order ONLINE too)
PLATINUM POLYMER
2-Cell Lithium Polymer Packs – with JST-BEC conn’s.
#2LP300* 7.4v 300mAh Li-POLY pk (13 gms/0.46oz) $20.95
#2LP400 7.4v 400mAh Li-POLY pk(18 gms/ 0.64oz) $18.95
#2LP650 7.4v 650mAh Li-POLY pk (28 gms/ 1 oz) $20.95
#2LP800* 7.4v 800mAh Li-POLY pk (34 gms/ 1.2oz) $27.95
#2LP900 7.4v 900mAh Li-POLY pk (38 gms/ 1.35oz)$23.95
#2LP1200 7.4v 1200mAh Li-POLY pk (48 gms/1.7oz) $25.95
#2LP1500*7.4v 1500mAh Li-POLY pk (62 gms/2.2oz) $39.95
#2LP1700 7.4v 1700mAh Li-POLY pk (68 gms/2.4 oz) $31.95
#2LP1900 7.4v 1900mAh Li-POLY pk (76 gms/2.7oz) $34.95
#2LP2200 7.4v 2200mAh Li-POLY pk (88 gms/3.3 oz) $38.95
*300, 800, & 1500mAh are HIGHER-AMP packs ( 5C discharge!)
QN-012BC charger QN-012DC charger VR5.4 / VR6.0
#QN-012BC Fast-Smart Charger (AC) for Li-POLY pk. $19.95
#QN-012DC Fast-Smart 12VDC charger for Li-POLYpk. $19.95
#VR5.4 Voltage Regulator –limits output to 5.4V max $19.95
#VR6.0 Voltage Regulator –limits output to 6.0V max $19.95
NEW Lithium Polymer cells – with E-Z solder tabs !
#P145 3.7v 145mAh Li-POLYcell (4 gms / 0.13 oz)$ 5.95ea
#P300* 3.7v 300mAh Li-POLYcell (6.5 gms /.23 oz)$ 7.95ea
#P400 3.7v 400mAh Li-POLYcell (9 gms / 0.32oz) $ 6.95ea
#P650 3.7v 650mAh Li-POLYcell (14 gms / 0.5 oz) $ 7.95ea
#P800* 3.7v 800mAh Li-POLYcell (17 gms / 0.6 oz) $10.95ea
#P900 3.7v 900mAh Li-POLYcell (19 gms/ 0.67oz) $ 9.95ea
#P1200 3.7v 1200mAh Li-POLY cell (24 gms/0.85oz) $10.95ea
#P1500*3.7v 1500mAh Li-POLY cell (31 gms/1.1oz) $15.95ea
#P1700 3.7v 1700mAh Li-POLY cell (34 gms/1.2oz) $12.95ea
#P1900 3.7v 1900mAh Li-POLY cell (38 gms/1.35oz)$13.95ea
#P2200 3.7v 2200mAh Li-POLY cell(44 gms/1.65oz)$14.95ea
*300, 800, & 1500mAh are HIGHER-AMP packs ( 5C discharge!)
Motor packs, R/C packs, TX packs, & more!
New HiCell electric flight Ni-MH packs!
For park flyers, etc. Shapes: A=Flat; B=twin-stick; C=two rows;
D=four sticks. JST conn.=add $3.00. Deans Ultra conn.=add $5.
Cell # size / mAh / $ each 7.2v 8.4v 9.6v 10.8v 12.0v
AP-350 1/3AA, 350mAh $2.50 $23.95 $26.95 $29.95 $32.95 $35.95
AP-700 2/3AA, 700mAh $2.50 $23.95 $26.95 $29.95 $32.95 $35.95
AP-1000 2/3A,1000mAh$3.00 $24.95 $27.95 $30.95 $33.95 $36.95
MOTOR PACKS w/ SANYO Ni-Cd cells (no connector):
Shapes (see above). Add deans ULTRA connector for $5.00 xtra
Cell # size /mAh / $ each 7.2v 8.4v 9.6v 10.8v 12.0v
N-500AR(2/3A 500mA) $2.50 $20.00 $24.00 $28.00 $32.00 $36.00
KR600AE(2/3A 600mA) $1.95 $17.00 $20.00 $23.00 $26.00 $29.00
SANYO Receiver Packs w/ Connector! (Flat or Square)
Choose Futaba J, JR-HITEC-Z, or AIRTRONICS(old) plug!
4.8 volt 700mAh (Standard AA NiCd, w/conn.) $ 9.95ea.
4.8 volt 1100mAh (long-life AA NiCd, w/conn.) $13.95ea.
4.8 volt 1700mAh (KR-1700AU Ni-Cd, w/conn.)$17.95ea.
4.8 volt 2100mAh (ULTRA AA Ni-MH, w/conn.) $19.95ea.
New & improved HEAVY 22-guage Connectors !
Specify Futaba J (FM), JR-HiTEC-Airt. Z, or AIRTRONICS(old)
Male or Female (1 end): $ 2.00 / 3”or 6” Extn: $ 3.25
12” Extn: $ 3.50 / 24” Extn: $ 4.00 / 36” Extn:$ 4.50
Y-connector:$5.50 ea / Switch Harness:$6.50ea
SANYO Transmitter Packs w/leads. Shapes shown above
Choose SQUARE(D) or Side-by-Side (A). Add TX plug for $3.00.
9.6 volt 700mAh (square or SxS, w/ leads) $16.95ea.
9.6 volt 1100mAh (square or SxS, w/ leads) $22.95ea.
9.6 volt 1650mAh (Ni-MH square or SxS, w/ leads )$29.95ea.
Mail, Phone, Fax, or E-mail us. Pay w/ MC, VISA, DISC, AMEX
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E-mail to us at: [email protected] S&H: $7.00 min.
“vibration mode” is longitudinal.
There’s a torsional vibration mode too,
caused by the once-per-revolution power
impulses that drive the propeller.
The total vibratory effect is far from
severe, yet it does differ quite a bit from
that of conventional model engines. So
for safety’s sake I recommend using a
firmly attached hard-plywood firewall
that is at least 3⁄16 inch thick for the 60-
size RCV and 1⁄4-inch minimum for the
90 and 120 RCVs.
Now for the “port position change” I
mentioned earlier. RCV SP engines are
assembled at the factory with the
carburetor assembly on the bottom, the
glow plug on the right, and the muffler
on the left side (as seen facing the
propeller).
I broke in my 60-SP set up that way.
But to install this engine in an RC model
design of mine, it’s more convenient for
my airplane configuration to have the
muffler at the bottom and the carburetor
on one side. The RCV SP engines allow
this change to be easily made. In fact,
their instruction manuals tell you
exactly how to do the job—including
correctly “retiming” the rotary valve.
I’m not the only one who is
powerfully impressed by RCV’s
innovative approach to four-stroke
engine design. A major American
corporation recently awarded RCV a
multimillion-dollar development
contract for industrial applications of its
patented rotary-cylinder-valve fourstroke
engines!
More Engine News: Stefan Gasparin
has discontinued making his fabulous
line of CO2 motors. Also, AeroDyne has
gone out of business, depriving West
Coast modelers of a convenient source
for excellent-quality model diesel fuel.
Rossi engines have a new US
importer: SG Model Engines, Box
280303, Northridge CA 91328; Web
site: http://shop.vendio.com/
RossiEnginesUSA. In my next column
I’ll report on the latest Rossi RC .60
engine, but for now I want to tell you
about the company’s glow plugs.
Since its start-up in the 1960s, Rossi
has been strongly involved in model
racing—airplanes, cars, and boats.
Because of that background, it has
developed an amazingly comprehensive
line of glow plugs.
Rossi offers plugs in seven different
heat ranges for nonthrottled engines.
(The smallest engines need the hottest
plugs because their surface cooling
areas are larger in proportion to their
displacement than large-size glows.
Those require cold-range plugs.)
Rossi also makes RC-type glow
plugs in two heat ranges: Hot for
engines less than .24 cu. in. and Cold for
larger sizes. There’s a special Rossi
glow plug for four-stroke model engines
too. MA
09sig3QXD 6/24/04 8:37 am Page 79
Edition: Model Aviation - 2004/09
Page Numbers: 76,77,79
Edition: Model Aviation - 2004/09
Page Numbers: 76,77,79
76 MODEL AVIATION
IN RECENT COLUMNS I discussed the unusual valveless
four-stroke model engines made by the British RCV company
(www.rcvengines.com). The results of my tests on its RCV58-CD
(“CD” means Crankshaft Drive) impressed me so greatly that I
soon acquired one of the “in-line” engines: the RCV60-SP.
(These in-line power plants are also available in 90 and 120 cu.
in. displacements.)
This extraordinary design differs in almost every way from
any model engine I’ve ever run. Besides providing the rotary
intake and exhaust valve functions for the 60-SP’s four-stroke
operation, its 2:1 gear-driven rotating cylinder sleeve also drives
the propeller. That makes the propeller rpm exactly half that of
the engine’s crankshaft.
This gearing-down feature allows the 60-SP to turn largediameter,
high-pitch propellers. From that it gains the same
efficiency improvement that so many of today’s electric-powered
RC models get from their reduction gears.
RCV recommends the APC 16 x 12 propeller for the 60-SP.
I’ve tried that, a Master Airscrew Classic 18 x 8, and two 16 x 8s
with wider blades than APC uses. All ran well on the 60-SP at
full-throttle propeller rpm between 4,400 (with the 18 x 8) and
5,300 (using either 16 x 8). (RCV advises a maximum propeller
speed of roughly 5,500 rpm, to avoid any possibility of damage
from over-revving.)
RCV engines (both types) use the lowest-height pistons I’ve
ever seen in model engines. The side height of the 60’s piston is
just half its diameter.
(For 70 years the usual practice for model-engine pistons has
been to make them at least as tall as their diameters. The idea
was to resist “piston cocking”—a tendency to tilt from the side
force exerted on the piston by its connecting rod whenever the
rod is in any position during its travel other than straight along
the cylinder centerline.)
After breaking in my 60-SP, I took it apart—to check for
Joe Wagner
T h e E n g i n e S h o p
212 S. Pine Ave., Ozark AL 36360
The British-made RCV60-SP comes with all necessary mounting
hardware. No separate engine mount is needed.
The optional accessory starting adapter fits into hex socket
screw at engine’s rear. It makes starting positive and safe.
Starting the 60-SP is quick and easy. (The test stand shown has
provisions for running several engines at once.)
The in-line configuration makes neatly cowled-in installations
easy. The small muffler does a fine job of sound reduction.
09sig3QXD 6/24/04 8:37 am Page 76
signs of wear and reposition its ports.
(More about that later in this column.) I
found no visible wear to anything! The
RCV’s steel piston (equipped with a
single thin ring) showed no trace of side
scuffing, despite its shortness. One reason
for that is the RCV’s hardened-steel
cylinder sleeve has a smooth, continuous
bore. It needs no port cutouts. That lets
the piston move with uniform,
uninterrupted side support from one end
of its stroke to the other.
I also closely examined the gear teeth.
Previous in-line model-engine designs
using bevel gear drives (e.g., the twostroke
glow .29s my old friend Clarence
Lee made 50 years ago) suffered geartooth
breakage. That was from fatigue
failure caused by the fact that the same
tooth on the “driving” gear had to absorb
the impact from each firing impulse from
the piston over and over and over—200
times every second the engine ran.
This isn’t a problem in the RCV
designs! They use hardened-steel helicaltype
bevel gears which distribute the peak
driving impulses over two meshing teeth
in each gear rather than just one.
Looking into the 60-SP’s operating
principle in detail, it has a conventional
piston, a connecting rod, and a crankshaft
assembly. The crankshaft spins in dual
ball bearings and includes a bevel gear.
That drives a mating 2:1 gear on the
cylinder sleeve’s base. At the front end of
the rotating cylinder (which also runs in
dual ball bearings) is the combustionchamber
section; ahead of that is the
propeller drive shaft.
The RCV’s combustion chamber—with
an inside diameter of approximately half
the cylinder bore—has a single radial port
September 2004 77
Partial disassembly shows RCV’s construction. Crankcase and
shaft are at left; gear-driven rotary sleeve drive is at right.
Rossi’s amazingly wide range of glow plugs provides maximum
power options for any size and type of glow engine.
Since 1948 Fox Manufacturing
Company has been producing
high quality model airplane
engines, glow plugs and other
accessories. Fox has become a
name modelers can trust when
it comes to durability, power,
and performance at an
affordable price. (479) 646-1656
Fax (479) 646-1757
5305 Towson Avenue
Fort Smith, AR 72901
www.foxmanufacturing.com
email: [email protected]
09sig3QXD 6/24/04 8:37 am Page 77
September 2004 79
on its side. As the sleeve spins, this port
lines up first with the intake (carburetor)
opening to admit a fresh fuel/air charge,
then with the glow plug for the firing
stroke, and then with the exhaust. This
cycle repeats for each revolution of the
propeller.
As with conventional-design fourstroke
model engines, the RCV’s
incoming fuel/air mixture doesn’t pass
through the crankcase. Yet the moving
parts there—plus all four ball
bearings—receive more than adequate
lubrication. That comes from oil the
combustion pressure forces through the
minute clearance gaps between the
rotating sleeve and its outer housing.
My RCV60-SP runs quite cleanly, yet
the utter lack of moving-parts wear—
including the gear teeth—after more
than two hours of test running shows
that they’re well lubricated indeed.
The SP-series RCV engines require
“radial mounting” to a solid-plywood
firewall. To ensure firm attachment,
they come with a metal backplate (for
the rear side of the firewall) and a set of
socket-head metric capscrews and
washers. I found mounting the RCV a
bit tedious because the capscrews are
located close to the engine case. A onequarter
turn at a time with a standard
Allen wrench was all I could manage.
Starting an RCV SP engine is also
different! The external end of its
crankshaft contains a socket-head screw
used as a driver key, and a separately
available adapter fitted onto the shaft of
a standard electric starter provides the
starting action. (I tried several times to
start my 60-SP by hand-flipping the
propeller. It didn’t work.)
RCV engines start best when rather
“wet.” I finger-choke the carburetor
inlet while hand-flipping the propeller
until I can feel fuel against my fingertip.
Then I connect the glow plug and apply
the starter with the throttle set slightly
less than half open. The RCV fires right
up!
I use Omega 10%-nitromethane fourstroke
fuel. It meets RCV’s
recommendations for nitromethane
content and oil percentage exactly and
provides plenty of power. In fact, I had
to attach an “anchor cable” to my
portable engine test stand to prevent
full-throttle thrust from the 18-inch
propeller from pulling that 40+-pound
rig around on my workshop’s deck.
Complete with its mounting plate,
screws, and muffler, the 60-SP weighs
23 ounces. (For comparison, the new
Rossi two-stroke .60 weighs 28 ounces
with its muffler but without a mount.)
However, the 60-SP is somewhat bulky;
it’s noticeably bigger than an O.S. FS-
70 II Surpass.
While test-running my 60-SP, I
noticed its distinctly different “feel.”
Because its piston runs fore and aft
instead of up and down, the main
Mr. NiCd’s BATTERIES AMERICA
www.batteriesamerica.com
Summer 2004 Specials (Order ONLINE too)
PLATINUM POLYMER
2-Cell Lithium Polymer Packs – with JST-BEC conn’s.
#2LP300* 7.4v 300mAh Li-POLY pk (13 gms/0.46oz) $20.95
#2LP400 7.4v 400mAh Li-POLY pk(18 gms/ 0.64oz) $18.95
#2LP650 7.4v 650mAh Li-POLY pk (28 gms/ 1 oz) $20.95
#2LP800* 7.4v 800mAh Li-POLY pk (34 gms/ 1.2oz) $27.95
#2LP900 7.4v 900mAh Li-POLY pk (38 gms/ 1.35oz)$23.95
#2LP1200 7.4v 1200mAh Li-POLY pk (48 gms/1.7oz) $25.95
#2LP1500*7.4v 1500mAh Li-POLY pk (62 gms/2.2oz) $39.95
#2LP1700 7.4v 1700mAh Li-POLY pk (68 gms/2.4 oz) $31.95
#2LP1900 7.4v 1900mAh Li-POLY pk (76 gms/2.7oz) $34.95
#2LP2200 7.4v 2200mAh Li-POLY pk (88 gms/3.3 oz) $38.95
*300, 800, & 1500mAh are HIGHER-AMP packs ( 5C discharge!)
QN-012BC charger QN-012DC charger VR5.4 / VR6.0
#QN-012BC Fast-Smart Charger (AC) for Li-POLY pk. $19.95
#QN-012DC Fast-Smart 12VDC charger for Li-POLYpk. $19.95
#VR5.4 Voltage Regulator –limits output to 5.4V max $19.95
#VR6.0 Voltage Regulator –limits output to 6.0V max $19.95
NEW Lithium Polymer cells – with E-Z solder tabs !
#P145 3.7v 145mAh Li-POLYcell (4 gms / 0.13 oz)$ 5.95ea
#P300* 3.7v 300mAh Li-POLYcell (6.5 gms /.23 oz)$ 7.95ea
#P400 3.7v 400mAh Li-POLYcell (9 gms / 0.32oz) $ 6.95ea
#P650 3.7v 650mAh Li-POLYcell (14 gms / 0.5 oz) $ 7.95ea
#P800* 3.7v 800mAh Li-POLYcell (17 gms / 0.6 oz) $10.95ea
#P900 3.7v 900mAh Li-POLYcell (19 gms/ 0.67oz) $ 9.95ea
#P1200 3.7v 1200mAh Li-POLY cell (24 gms/0.85oz) $10.95ea
#P1500*3.7v 1500mAh Li-POLY cell (31 gms/1.1oz) $15.95ea
#P1700 3.7v 1700mAh Li-POLY cell (34 gms/1.2oz) $12.95ea
#P1900 3.7v 1900mAh Li-POLY cell (38 gms/1.35oz)$13.95ea
#P2200 3.7v 2200mAh Li-POLY cell(44 gms/1.65oz)$14.95ea
*300, 800, & 1500mAh are HIGHER-AMP packs ( 5C discharge!)
Motor packs, R/C packs, TX packs, & more!
New HiCell electric flight Ni-MH packs!
For park flyers, etc. Shapes: A=Flat; B=twin-stick; C=two rows;
D=four sticks. JST conn.=add $3.00. Deans Ultra conn.=add $5.
Cell # size / mAh / $ each 7.2v 8.4v 9.6v 10.8v 12.0v
AP-350 1/3AA, 350mAh $2.50 $23.95 $26.95 $29.95 $32.95 $35.95
AP-700 2/3AA, 700mAh $2.50 $23.95 $26.95 $29.95 $32.95 $35.95
AP-1000 2/3A,1000mAh$3.00 $24.95 $27.95 $30.95 $33.95 $36.95
MOTOR PACKS w/ SANYO Ni-Cd cells (no connector):
Shapes (see above). Add deans ULTRA connector for $5.00 xtra
Cell # size /mAh / $ each 7.2v 8.4v 9.6v 10.8v 12.0v
N-500AR(2/3A 500mA) $2.50 $20.00 $24.00 $28.00 $32.00 $36.00
KR600AE(2/3A 600mA) $1.95 $17.00 $20.00 $23.00 $26.00 $29.00
SANYO Receiver Packs w/ Connector! (Flat or Square)
Choose Futaba J, JR-HITEC-Z, or AIRTRONICS(old) plug!
4.8 volt 700mAh (Standard AA NiCd, w/conn.) $ 9.95ea.
4.8 volt 1100mAh (long-life AA NiCd, w/conn.) $13.95ea.
4.8 volt 1700mAh (KR-1700AU Ni-Cd, w/conn.)$17.95ea.
4.8 volt 2100mAh (ULTRA AA Ni-MH, w/conn.) $19.95ea.
New & improved HEAVY 22-guage Connectors !
Specify Futaba J (FM), JR-HiTEC-Airt. Z, or AIRTRONICS(old)
Male or Female (1 end): $ 2.00 / 3”or 6” Extn: $ 3.25
12” Extn: $ 3.50 / 24” Extn: $ 4.00 / 36” Extn:$ 4.50
Y-connector:$5.50 ea / Switch Harness:$6.50ea
SANYO Transmitter Packs w/leads. Shapes shown above
Choose SQUARE(D) or Side-by-Side (A). Add TX plug for $3.00.
9.6 volt 700mAh (square or SxS, w/ leads) $16.95ea.
9.6 volt 1100mAh (square or SxS, w/ leads) $22.95ea.
9.6 volt 1650mAh (Ni-MH square or SxS, w/ leads )$29.95ea.
Mail, Phone, Fax, or E-mail us. Pay w/ MC, VISA, DISC, AMEX
CALL OR WRITE FOR OUR FREE CATALOG
BATTERIES AMERICA 2211-D Parview Rd,
Middleton, WI 53562. To order, call TOLL FREE:
1-800-308-4805
Inquiries: 608-831-3443 / Fax: 608-831-1082
E-mail to us at: [email protected] S&H: $7.00 min.
“vibration mode” is longitudinal.
There’s a torsional vibration mode too,
caused by the once-per-revolution power
impulses that drive the propeller.
The total vibratory effect is far from
severe, yet it does differ quite a bit from
that of conventional model engines. So
for safety’s sake I recommend using a
firmly attached hard-plywood firewall
that is at least 3⁄16 inch thick for the 60-
size RCV and 1⁄4-inch minimum for the
90 and 120 RCVs.
Now for the “port position change” I
mentioned earlier. RCV SP engines are
assembled at the factory with the
carburetor assembly on the bottom, the
glow plug on the right, and the muffler
on the left side (as seen facing the
propeller).
I broke in my 60-SP set up that way.
But to install this engine in an RC model
design of mine, it’s more convenient for
my airplane configuration to have the
muffler at the bottom and the carburetor
on one side. The RCV SP engines allow
this change to be easily made. In fact,
their instruction manuals tell you
exactly how to do the job—including
correctly “retiming” the rotary valve.
I’m not the only one who is
powerfully impressed by RCV’s
innovative approach to four-stroke
engine design. A major American
corporation recently awarded RCV a
multimillion-dollar development
contract for industrial applications of its
patented rotary-cylinder-valve fourstroke
engines!
More Engine News: Stefan Gasparin
has discontinued making his fabulous
line of CO2 motors. Also, AeroDyne has
gone out of business, depriving West
Coast modelers of a convenient source
for excellent-quality model diesel fuel.
Rossi engines have a new US
importer: SG Model Engines, Box
280303, Northridge CA 91328; Web
site: http://shop.vendio.com/
RossiEnginesUSA. In my next column
I’ll report on the latest Rossi RC .60
engine, but for now I want to tell you
about the company’s glow plugs.
Since its start-up in the 1960s, Rossi
has been strongly involved in model
racing—airplanes, cars, and boats.
Because of that background, it has
developed an amazingly comprehensive
line of glow plugs.
Rossi offers plugs in seven different
heat ranges for nonthrottled engines.
(The smallest engines need the hottest
plugs because their surface cooling
areas are larger in proportion to their
displacement than large-size glows.
Those require cold-range plugs.)
Rossi also makes RC-type glow
plugs in two heat ranges: Hot for
engines less than .24 cu. in. and Cold for
larger sizes. There’s a special Rossi
glow plug for four-stroke model engines
too. MA
09sig3QXD 6/24/04 8:37 am Page 79
Edition: Model Aviation - 2004/09
Page Numbers: 76,77,79
76 MODEL AVIATION
IN RECENT COLUMNS I discussed the unusual valveless
four-stroke model engines made by the British RCV company
(www.rcvengines.com). The results of my tests on its RCV58-CD
(“CD” means Crankshaft Drive) impressed me so greatly that I
soon acquired one of the “in-line” engines: the RCV60-SP.
(These in-line power plants are also available in 90 and 120 cu.
in. displacements.)
This extraordinary design differs in almost every way from
any model engine I’ve ever run. Besides providing the rotary
intake and exhaust valve functions for the 60-SP’s four-stroke
operation, its 2:1 gear-driven rotating cylinder sleeve also drives
the propeller. That makes the propeller rpm exactly half that of
the engine’s crankshaft.
This gearing-down feature allows the 60-SP to turn largediameter,
high-pitch propellers. From that it gains the same
efficiency improvement that so many of today’s electric-powered
RC models get from their reduction gears.
RCV recommends the APC 16 x 12 propeller for the 60-SP.
I’ve tried that, a Master Airscrew Classic 18 x 8, and two 16 x 8s
with wider blades than APC uses. All ran well on the 60-SP at
full-throttle propeller rpm between 4,400 (with the 18 x 8) and
5,300 (using either 16 x 8). (RCV advises a maximum propeller
speed of roughly 5,500 rpm, to avoid any possibility of damage
from over-revving.)
RCV engines (both types) use the lowest-height pistons I’ve
ever seen in model engines. The side height of the 60’s piston is
just half its diameter.
(For 70 years the usual practice for model-engine pistons has
been to make them at least as tall as their diameters. The idea
was to resist “piston cocking”—a tendency to tilt from the side
force exerted on the piston by its connecting rod whenever the
rod is in any position during its travel other than straight along
the cylinder centerline.)
After breaking in my 60-SP, I took it apart—to check for
Joe Wagner
T h e E n g i n e S h o p
212 S. Pine Ave., Ozark AL 36360
The British-made RCV60-SP comes with all necessary mounting
hardware. No separate engine mount is needed.
The optional accessory starting adapter fits into hex socket
screw at engine’s rear. It makes starting positive and safe.
Starting the 60-SP is quick and easy. (The test stand shown has
provisions for running several engines at once.)
The in-line configuration makes neatly cowled-in installations
easy. The small muffler does a fine job of sound reduction.
09sig3QXD 6/24/04 8:37 am Page 76
signs of wear and reposition its ports.
(More about that later in this column.) I
found no visible wear to anything! The
RCV’s steel piston (equipped with a
single thin ring) showed no trace of side
scuffing, despite its shortness. One reason
for that is the RCV’s hardened-steel
cylinder sleeve has a smooth, continuous
bore. It needs no port cutouts. That lets
the piston move with uniform,
uninterrupted side support from one end
of its stroke to the other.
I also closely examined the gear teeth.
Previous in-line model-engine designs
using bevel gear drives (e.g., the twostroke
glow .29s my old friend Clarence
Lee made 50 years ago) suffered geartooth
breakage. That was from fatigue
failure caused by the fact that the same
tooth on the “driving” gear had to absorb
the impact from each firing impulse from
the piston over and over and over—200
times every second the engine ran.
This isn’t a problem in the RCV
designs! They use hardened-steel helicaltype
bevel gears which distribute the peak
driving impulses over two meshing teeth
in each gear rather than just one.
Looking into the 60-SP’s operating
principle in detail, it has a conventional
piston, a connecting rod, and a crankshaft
assembly. The crankshaft spins in dual
ball bearings and includes a bevel gear.
That drives a mating 2:1 gear on the
cylinder sleeve’s base. At the front end of
the rotating cylinder (which also runs in
dual ball bearings) is the combustionchamber
section; ahead of that is the
propeller drive shaft.
The RCV’s combustion chamber—with
an inside diameter of approximately half
the cylinder bore—has a single radial port
September 2004 77
Partial disassembly shows RCV’s construction. Crankcase and
shaft are at left; gear-driven rotary sleeve drive is at right.
Rossi’s amazingly wide range of glow plugs provides maximum
power options for any size and type of glow engine.
Since 1948 Fox Manufacturing
Company has been producing
high quality model airplane
engines, glow plugs and other
accessories. Fox has become a
name modelers can trust when
it comes to durability, power,
and performance at an
affordable price. (479) 646-1656
Fax (479) 646-1757
5305 Towson Avenue
Fort Smith, AR 72901
www.foxmanufacturing.com
email: [email protected]
09sig3QXD 6/24/04 8:37 am Page 77
September 2004 79
on its side. As the sleeve spins, this port
lines up first with the intake (carburetor)
opening to admit a fresh fuel/air charge,
then with the glow plug for the firing
stroke, and then with the exhaust. This
cycle repeats for each revolution of the
propeller.
As with conventional-design fourstroke
model engines, the RCV’s
incoming fuel/air mixture doesn’t pass
through the crankcase. Yet the moving
parts there—plus all four ball
bearings—receive more than adequate
lubrication. That comes from oil the
combustion pressure forces through the
minute clearance gaps between the
rotating sleeve and its outer housing.
My RCV60-SP runs quite cleanly, yet
the utter lack of moving-parts wear—
including the gear teeth—after more
than two hours of test running shows
that they’re well lubricated indeed.
The SP-series RCV engines require
“radial mounting” to a solid-plywood
firewall. To ensure firm attachment,
they come with a metal backplate (for
the rear side of the firewall) and a set of
socket-head metric capscrews and
washers. I found mounting the RCV a
bit tedious because the capscrews are
located close to the engine case. A onequarter
turn at a time with a standard
Allen wrench was all I could manage.
Starting an RCV SP engine is also
different! The external end of its
crankshaft contains a socket-head screw
used as a driver key, and a separately
available adapter fitted onto the shaft of
a standard electric starter provides the
starting action. (I tried several times to
start my 60-SP by hand-flipping the
propeller. It didn’t work.)
RCV engines start best when rather
“wet.” I finger-choke the carburetor
inlet while hand-flipping the propeller
until I can feel fuel against my fingertip.
Then I connect the glow plug and apply
the starter with the throttle set slightly
less than half open. The RCV fires right
up!
I use Omega 10%-nitromethane fourstroke
fuel. It meets RCV’s
recommendations for nitromethane
content and oil percentage exactly and
provides plenty of power. In fact, I had
to attach an “anchor cable” to my
portable engine test stand to prevent
full-throttle thrust from the 18-inch
propeller from pulling that 40+-pound
rig around on my workshop’s deck.
Complete with its mounting plate,
screws, and muffler, the 60-SP weighs
23 ounces. (For comparison, the new
Rossi two-stroke .60 weighs 28 ounces
with its muffler but without a mount.)
However, the 60-SP is somewhat bulky;
it’s noticeably bigger than an O.S. FS-
70 II Surpass.
While test-running my 60-SP, I
noticed its distinctly different “feel.”
Because its piston runs fore and aft
instead of up and down, the main
Mr. NiCd’s BATTERIES AMERICA
www.batteriesamerica.com
Summer 2004 Specials (Order ONLINE too)
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2-Cell Lithium Polymer Packs – with JST-BEC conn’s.
#2LP300* 7.4v 300mAh Li-POLY pk (13 gms/0.46oz) $20.95
#2LP400 7.4v 400mAh Li-POLY pk(18 gms/ 0.64oz) $18.95
#2LP650 7.4v 650mAh Li-POLY pk (28 gms/ 1 oz) $20.95
#2LP800* 7.4v 800mAh Li-POLY pk (34 gms/ 1.2oz) $27.95
#2LP900 7.4v 900mAh Li-POLY pk (38 gms/ 1.35oz)$23.95
#2LP1200 7.4v 1200mAh Li-POLY pk (48 gms/1.7oz) $25.95
#2LP1500*7.4v 1500mAh Li-POLY pk (62 gms/2.2oz) $39.95
#2LP1700 7.4v 1700mAh Li-POLY pk (68 gms/2.4 oz) $31.95
#2LP1900 7.4v 1900mAh Li-POLY pk (76 gms/2.7oz) $34.95
#2LP2200 7.4v 2200mAh Li-POLY pk (88 gms/3.3 oz) $38.95
*300, 800, & 1500mAh are HIGHER-AMP packs ( 5C discharge!)
QN-012BC charger QN-012DC charger VR5.4 / VR6.0
#QN-012BC Fast-Smart Charger (AC) for Li-POLY pk. $19.95
#QN-012DC Fast-Smart 12VDC charger for Li-POLYpk. $19.95
#VR5.4 Voltage Regulator –limits output to 5.4V max $19.95
#VR6.0 Voltage Regulator –limits output to 6.0V max $19.95
NEW Lithium Polymer cells – with E-Z solder tabs !
#P145 3.7v 145mAh Li-POLYcell (4 gms / 0.13 oz)$ 5.95ea
#P300* 3.7v 300mAh Li-POLYcell (6.5 gms /.23 oz)$ 7.95ea
#P400 3.7v 400mAh Li-POLYcell (9 gms / 0.32oz) $ 6.95ea
#P650 3.7v 650mAh Li-POLYcell (14 gms / 0.5 oz) $ 7.95ea
#P800* 3.7v 800mAh Li-POLYcell (17 gms / 0.6 oz) $10.95ea
#P900 3.7v 900mAh Li-POLYcell (19 gms/ 0.67oz) $ 9.95ea
#P1200 3.7v 1200mAh Li-POLY cell (24 gms/0.85oz) $10.95ea
#P1500*3.7v 1500mAh Li-POLY cell (31 gms/1.1oz) $15.95ea
#P1700 3.7v 1700mAh Li-POLY cell (34 gms/1.2oz) $12.95ea
#P1900 3.7v 1900mAh Li-POLY cell (38 gms/1.35oz)$13.95ea
#P2200 3.7v 2200mAh Li-POLY cell(44 gms/1.65oz)$14.95ea
*300, 800, & 1500mAh are HIGHER-AMP packs ( 5C discharge!)
Motor packs, R/C packs, TX packs, & more!
New HiCell electric flight Ni-MH packs!
For park flyers, etc. Shapes: A=Flat; B=twin-stick; C=two rows;
D=four sticks. JST conn.=add $3.00. Deans Ultra conn.=add $5.
Cell # size / mAh / $ each 7.2v 8.4v 9.6v 10.8v 12.0v
AP-350 1/3AA, 350mAh $2.50 $23.95 $26.95 $29.95 $32.95 $35.95
AP-700 2/3AA, 700mAh $2.50 $23.95 $26.95 $29.95 $32.95 $35.95
AP-1000 2/3A,1000mAh$3.00 $24.95 $27.95 $30.95 $33.95 $36.95
MOTOR PACKS w/ SANYO Ni-Cd cells (no connector):
Shapes (see above). Add deans ULTRA connector for $5.00 xtra
Cell # size /mAh / $ each 7.2v 8.4v 9.6v 10.8v 12.0v
N-500AR(2/3A 500mA) $2.50 $20.00 $24.00 $28.00 $32.00 $36.00
KR600AE(2/3A 600mA) $1.95 $17.00 $20.00 $23.00 $26.00 $29.00
SANYO Receiver Packs w/ Connector! (Flat or Square)
Choose Futaba J, JR-HITEC-Z, or AIRTRONICS(old) plug!
4.8 volt 700mAh (Standard AA NiCd, w/conn.) $ 9.95ea.
4.8 volt 1100mAh (long-life AA NiCd, w/conn.) $13.95ea.
4.8 volt 1700mAh (KR-1700AU Ni-Cd, w/conn.)$17.95ea.
4.8 volt 2100mAh (ULTRA AA Ni-MH, w/conn.) $19.95ea.
New & improved HEAVY 22-guage Connectors !
Specify Futaba J (FM), JR-HiTEC-Airt. Z, or AIRTRONICS(old)
Male or Female (1 end): $ 2.00 / 3”or 6” Extn: $ 3.25
12” Extn: $ 3.50 / 24” Extn: $ 4.00 / 36” Extn:$ 4.50
Y-connector:$5.50 ea / Switch Harness:$6.50ea
SANYO Transmitter Packs w/leads. Shapes shown above
Choose SQUARE(D) or Side-by-Side (A). Add TX plug for $3.00.
9.6 volt 700mAh (square or SxS, w/ leads) $16.95ea.
9.6 volt 1100mAh (square or SxS, w/ leads) $22.95ea.
9.6 volt 1650mAh (Ni-MH square or SxS, w/ leads )$29.95ea.
Mail, Phone, Fax, or E-mail us. Pay w/ MC, VISA, DISC, AMEX
CALL OR WRITE FOR OUR FREE CATALOG
BATTERIES AMERICA 2211-D Parview Rd,
Middleton, WI 53562. To order, call TOLL FREE:
1-800-308-4805
Inquiries: 608-831-3443 / Fax: 608-831-1082
E-mail to us at: [email protected] S&H: $7.00 min.
“vibration mode” is longitudinal.
There’s a torsional vibration mode too,
caused by the once-per-revolution power
impulses that drive the propeller.
The total vibratory effect is far from
severe, yet it does differ quite a bit from
that of conventional model engines. So
for safety’s sake I recommend using a
firmly attached hard-plywood firewall
that is at least 3⁄16 inch thick for the 60-
size RCV and 1⁄4-inch minimum for the
90 and 120 RCVs.
Now for the “port position change” I
mentioned earlier. RCV SP engines are
assembled at the factory with the
carburetor assembly on the bottom, the
glow plug on the right, and the muffler
on the left side (as seen facing the
propeller).
I broke in my 60-SP set up that way.
But to install this engine in an RC model
design of mine, it’s more convenient for
my airplane configuration to have the
muffler at the bottom and the carburetor
on one side. The RCV SP engines allow
this change to be easily made. In fact,
their instruction manuals tell you
exactly how to do the job—including
correctly “retiming” the rotary valve.
I’m not the only one who is
powerfully impressed by RCV’s
innovative approach to four-stroke
engine design. A major American
corporation recently awarded RCV a
multimillion-dollar development
contract for industrial applications of its
patented rotary-cylinder-valve fourstroke
engines!
More Engine News: Stefan Gasparin
has discontinued making his fabulous
line of CO2 motors. Also, AeroDyne has
gone out of business, depriving West
Coast modelers of a convenient source
for excellent-quality model diesel fuel.
Rossi engines have a new US
importer: SG Model Engines, Box
280303, Northridge CA 91328; Web
site: http://shop.vendio.com/
RossiEnginesUSA. In my next column
I’ll report on the latest Rossi RC .60
engine, but for now I want to tell you
about the company’s glow plugs.
Since its start-up in the 1960s, Rossi
has been strongly involved in model
racing—airplanes, cars, and boats.
Because of that background, it has
developed an amazingly comprehensive
line of glow plugs.
Rossi offers plugs in seven different
heat ranges for nonthrottled engines.
(The smallest engines need the hottest
plugs because their surface cooling
areas are larger in proportion to their
displacement than large-size glows.
Those require cold-range plugs.)
Rossi also makes RC-type glow
plugs in two heat ranges: Hot for
engines less than .24 cu. in. and Cold for
larger sizes. There’s a special Rossi
glow plug for four-stroke model engines
too. MA
09sig3QXD 6/24/04 8:37 am Page 79